Weeping Rear Drive

[MotorcycleWriter]

To panic, or not to panic, that is the question.

 

Actually, I think not to panic. I have noticed that the rubber boot around the final drive universal weeps. Of course it is the rear, lower end of the boot. It isn't bad but it is there. Fortunately it isn't around the main bearing in the rear. Anyway, I figure a stitch in time saves nine so what's the course of action here? I like my bikes to be 100% spec and am up to the challenge. Maybe it'll finally give me a reason to go out and buy a heat gun!

 

Or would I be better off sending it to a pro for proper rebuild and shimming to make it last 100K miles? I've heard that final drive failures are due to quality control issues at the factory and proper shimming and preloads will virtually eliminate concerns.

 

-John

 

P.S. Just when the weather's gettin' good, too!

[dirtrider]

Morning John

 

Very first thing-- try to figure out which end of the drive shaft the leak is coming form. It can leak from the rear of the transmission then run down the inside of the swing arm then leak out from the rear of the final drive boot.

 

( IF ) a leak from the front area then you will need to dig into it & determine if the rear trans seal is leaking.

 

If nothing coming down from the front then more than likely you have a leaking final drive pinion seal. If so a bit of SEEPAGE can be normal but actual leaking isn't normal.

 

The pinion seal on the BMW 1100/1150 is a bit exacting to replace & requires special tools & through know how. It can be done at home (by making the special tools) but normally if a person is asking how they probably shouldn't be doing it.

 

In any case a lot of those pinion seals leak (or seeping heavily) is due to using modern (usually synthetic) gear oil as that oil is blended for low friction so has very little seal conditioner in it.

 

So first thing to try is to dump the gear oil from your final drive & replace it with standard 80w90 conventional) or better yet just plain 90 weight conventional (if you can find that). In a lot of cases that alone will stop the oil seepage. If it still seeps after some miles of riding then you will probably need to address the pinion seal.

 

[MotorcycleWriter]

Awesome! Thanks. I have noticed that it seems to have increased since I last changed the oil and replaced the dino-oil with Lucas synthetic. I will try that and see what happens. Looks pretty simple to pull the boot loose. Just cut the zip-tie, peel it back, and look inside. Don't figure there is anything special about the zip-tie is there?

 

The current buildup is from a thousand miles or so. Sort of a short black smudge just beneath the lower edge of the boot.

[Jim Moore]

Don't figure there is anything special about the zip-tie is there?

 

The current buildup is from a thousand miles or so. Sort of a short black smudge just beneath the lower edge of the boot.

 

Nothing special about the zip tie except it's about two feet long. You can also string together a couple of shorter ones.

 

That doesn't sound like anything to be concerned about. I'd wipe it off and check it again in a thousand miles.

[jbr7t]

My 04 1150R has a similar seep. Ive talke to two BMW mechanics and my personal mechanic adviser OopezoO all of whom said keep a check on the fluids but probably not a big deal unless its really LEAKING. Noticed it about 8k miles ago and all fluids still at proper level, so its def a small seep not LEAK..

[Clive Liddell]

I replaced the rear cable tie with the "official" BMW replacement hose clamp. Being able to nip it up stopped all signs of a weep from my bike and I take a look in there every two or three years with a piece of paper towel and mop up the approximately teaspoonful of oil...

 

 

[flars]

A tiny bit of oil makes a big mess on the front of the fd below the boot.

Loosen the boot, look up the tunnel. If nothing there, wipe the inside of the boot out with a rag and put the zip ties back on.

My RS has been seeping from the pinion end for the last 120,000 miles. My RT has been seeping for at least the last 40,000 miles. I wipe it off every month or two.

I use three zipties linked together.

 

[MotorcycleWriter]

What's a good source for the rear-drive boot clamp?

 

Until then, I'll use the zip ties.

[tomk99r11]

Zip ties work just fine, all you are trying to do is hold the boot in place, not really seal anything. Besides, if you use a tight clamp, you may be able to hide a problem that you really want to know is getting worse, if that happens. More likely to see the leakage with ZT's, IMO.

[Selden]

In any case a lot of those pinion seals leak (or seeping heavily) is due to using modern (usually synthetic) gear oil as that oil is blended for low friction so has very little seal conditioner in it.

Thanks for explaining your preference for non-synthetic gear oil.

[LBump]

What's a good source for the rear-drive boot clamp?

 

Until then, I'll use the zip ties.

 

Check line item 11 on the attached link. Otherwise use two zipties. It's just as easy to use two.

 

http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51765&catID=33&catname=Rear_axle,_rear-wheel_drive,_control&bindName=REAR_WHEEL_FORK&bindCat=33_1019

[MotorcycleWriter]

Pulled the boot this afternoon. There was about... 1/8 teaspoon of nice, golden lube pooled at the bottom of the swing arm. Maybe less. No residue anywhere else. I'm going to consider the matter closed for now. I used 24" zip-ties I picked up at Lowes for a couple fo bucks. Thanks for weighing in, everyone!

 

-John

[MotorcycleWriter]

What's a good source for the rear-drive boot clamp?

 

Until then, I'll use the zip ties.

 

Check line item 11 on the attached link. Otherwise use two zipties. It's just as easy to use two.

 

http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51765&catID=33&catname=Rear_axle,_rear-wheel_drive,_control&bindName=REAR_WHEEL_FORK&bindCat=33_1019

 

Are these metal and reusable? They look like worm-type clamps. Just collecting data. If they are reusable worm style band clamps I'll probably order some. If not reusable, I'll just go with the zip ties.

[BrianM]

They were reusable worm style clamps on my 1100.

[Trullion]

Mine too, same as my 850. When my 1100 sprung a slight leak there was a little misting at the joint between the gaiter and the clip. If I had an 1150 with this problem I'd probably buy the superior (reusable) 1100 part. (I assume that this would fit as AFAIK the FD units are the same).

[Uncle Beemer]

They are reusable. I have one on my 1500rt. However it's a bit loose and won't not snug up.